ipaddress_ioctl.c

snmp的源代码,已经在我的ubuntu下编译通过

/*
 *  Interface MIB architecture support
 *
 * $Id: ipaddress_ioctl.c,v 1.8 2004/10/19 03:23:01 rstory Exp $
 */
#include <net-snmp/net-snmp-config.h>
#include <net-snmp/net-snmp-includes.h>
#include "mibII/mibII_common.h"

#include <net-snmp/agent/net-snmp-agent-includes.h>
#include <net-snmp/data_access/ipaddress.h>
#include <net-snmp/data_access/interface.h>

#include "ip-mib/ipAddressTable/ipAddressTable_constants.h"
#include "if-mib/data_access/interface_ioctl.h"

#include <errno.h>
#include <net/if.h>
#include <sys/ioctl.h>

#include "ipaddress_ioctl.h"

static int _get_interface_count(int sd, struct ifconf * ifc);
static void _print_flags(short flags);

#define LIST_TOKEN "ioctl_extras"

/*
 * get extra structure
 *
 * @returns the extras structure from the entry
 */
_ioctl_extras *
netsnmp_ioctl_ipaddress_extras_get(netsnmp_ipaddress_entry *entry)
{
    if ((NULL == entry) || (NULL == entry->arch_data))
        return NULL;

    return netsnmp_get_list_data(entry->arch_data, LIST_TOKEN);
}

/**
 * initialize ioctl extras
 *
 * @returns _ioctl_extras pointer, or NULL on error
 */
_ioctl_extras *
netsnmp_ioctl_ipaddress_entry_init(netsnmp_ipaddress_entry *entry)
{
    netsnmp_data_list *node;
    _ioctl_extras     *extras;

    if (NULL == entry)
        return NULL;

    extras = SNMP_MALLOC_TYPEDEF(_ioctl_extras);
    if (NULL == extras)
        return NULL;

    node = netsnmp_create_data_list(LIST_TOKEN, extras, free);
    if (NULL == node) {
        free(extras);
        return NULL;
    }

    netsnmp_data_list_add_node( &entry->arch_data, node );
    
    return extras;
}

/**
 * cleanup ioctl extras
 */
void
netsnmp_ioctl_ipaddress_entry_cleanup(netsnmp_ipaddress_entry *entry)
{
    if (NULL == entry) {
        netsnmp_assert(NULL != entry);
        return;
    }

    if (NULL == entry->arch_data) {
        netsnmp_assert(NULL != entry->arch_data);
        return;
    }

    netsnmp_remove_list_node(&entry->arch_data, LIST_TOKEN);
}

/**
 * copy ioctl extras
 *
 * @retval  0: success
 * @retval <0: error
 */
int
netsnmp_ioctl_ipaddress_entry_copy(netsnmp_ipaddress_entry *lhs,
                                   netsnmp_ipaddress_entry *rhs)
{
    _ioctl_extras *lhs_extras, *rhs_extras;
    int            rc = SNMP_ERR_NOERROR;

    if ((NULL == lhs) || (NULL == rhs)) {
        netsnmp_assert((NULL != lhs) && (NULL != rhs));
        return -1;
    }

    rhs_extras = netsnmp_ioctl_ipaddress_extras_get(rhs);
    lhs_extras = netsnmp_ioctl_ipaddress_extras_get(lhs);
    if (NULL == rhs_extras) {
        if (NULL != lhs_extras)
            netsnmp_ioctl_ipaddress_entry_cleanup(lhs);
    }
    else {
        if (NULL == lhs_extras)
            lhs_extras = netsnmp_ioctl_ipaddress_entry_init(lhs);
        
        if (NULL != lhs_extras)
            memcpy(lhs_extras, rhs_extras, sizeof(_ioctl_extras));
        else
            rc = -1;
    }

    return rc;
}

/**
 * load ipv4 address via ioctl
 */
int
_netsnmp_ioctl_ipaddress_container_load_v4(netsnmp_container *container,
                                                  int idx_offset)
{
    int             i, sd, rc = 0, interfaces = 0;
    struct ifconf   ifc;
    struct ifreq   *ifrp;
    struct sockaddr save_addr;
    netsnmp_ipaddress_entry *entry;
    _ioctl_extras           *extras;

    if ((sd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        snmp_log(LOG_ERR, "could not create socket\n");
        return -1;
    }

    interfaces = _get_interface_count(sd, &ifc);
    if(interfaces < 0) {
        close(sd);
        return -2;
    }
    netsnmp_assert(NULL != ifc.ifc_buf);
    DEBUGMSGTL(("access:ipaddress:container", "processing %d interfaces\n", interfaces));

    ifrp = ifc.ifc_req;
    for(i=0; i < interfaces; ++i, ++ifrp) {

        DEBUGMSGTL(("access:ipaddress:container",
                    " interface %d, %s\n", i, ifrp->ifr_name));
        /*
         */
        entry = netsnmp_access_ipaddress_entry_create();
        if(NULL == entry) {
            rc = -3;
            break;
        }
        entry->ns_ia_index = ++idx_offset;

        /*
         * save if name
         */
        extras = netsnmp_ioctl_ipaddress_extras_get(entry);
        memcpy(extras->name, ifrp->ifr_name, sizeof(extras->name));

        /*
         * each time we make an ioctl, we need to specify the address, but
         * it will be overwritten in the call. so we save address here.
         */
        save_addr = ifrp->ifr_addr;

        /*
         * set indexes
         */
        switch(ifrp->ifr_addr.sa_family) {
            case AF_INET: {
                struct sockaddr_in * si =
                    (struct sockaddr_in *) &ifrp->ifr_addr;
                entry->ia_address_len = sizeof(si->sin_addr.s_addr);
                memcpy(entry->ia_address, &si->sin_addr.s_addr,
                       entry->ia_address_len);
            }
                break;
                
            case AF_INET6: {
                struct sockaddr_in6 * si =
                    (struct sockaddr_in6 *) &ifrp->ifr_addr;

                entry->ia_address_len = sizeof(si->sin6_addr.s6_addr);
                memcpy(entry->ia_address, &si->sin6_addr.s6_addr,
                       entry->ia_address_len);
            }
                break;

            default:
                snmp_log(LOG_ERR,"unknown if family %d\n",
                         ifrp->ifr_addr.sa_family);
                netsnmp_access_ipaddress_entry_free(entry);
                continue;
        }

        /*
         * get ifindex
         */
        {
            /*
             * I think that Linux and Solaris both use ':' in the
             * interface name for aliases. When a new arch is added
             * that uses some other indicator, a new function, maybe
             * netsnmp_access_ipaddress_entry_name_alias_check(), will
             * need to be written.
             */
            char *ptr = strchr(ifrp->ifr_name, ':');
            if (NULL != ptr) {
                entry->flags |= NETSNMP_ACCESS_IPADDRESS_ISALIAS;
                *ptr = 0;
            }
        }
        entry->if_index =
            netsnmp_access_interface_ioctl_ifindex_get(sd, ifrp->ifr_name);
        if (0 == entry->if_index) {
            snmp_log(LOG_ERR,"no ifindex found for interface\n");
            netsnmp_access_ipaddress_entry_free(entry);
            continue;
        }

        /*
         * get flags
         */
        ifrp->ifr_addr = save_addr;
        if (ioctl(sd, SIOCGIFFLAGS, ifrp) < 0) {
            snmp_log(LOG_ERR,
                     "error getting if_flags for interface %d\n", i);
            netsnmp_access_ipaddress_entry_free(entry);
            continue;
        }
        extras->flags = ifrp->ifr_flags;

        entry->ia_type = IPADDRESSTYPE_UNICAST; /* assume unicast? */

        /** entry->ia_prefix_oid ? */

        /*
         * per the MIB:
         *   In the absence of other information, an IPv4 address is
         *   always preferred(1).
         */
        entry->ia_status = IPADDRESSSTATUSTC_PREFERRED;

        /*
         * can we figure out if an address is from DHCP?
         * use manual until then...
         */
        entry->ia_origin = IPADDRESSORIGINTC_MANUAL;

        DEBUGIF("access:ipaddress:container") {
            DEBUGMSGT_NC(("access:ipaddress:container",
                          " if %d: addr len %d, index 0x%x\n",
                          i, entry->ia_address_len, entry->if_index));
            if (4 == entry->ia_address_len)
                DEBUGMSGT_NC(("access:ipaddress:container", " address %p\n",
                              *((void**)entry->ia_address)));
            DEBUGMSGT_NC(("access:ipaddress:container", "flags 0x%x\n",
                          extras->flags));
            _print_flags(extras->flags);

        }

        /*
         * add entry to container
         */
        CONTAINER_INSERT(container, entry);
    }

    /*
     * clean up
     */
    free(ifc.ifc_buf);
    close(sd);

    /*
     * return number of interfaces seen
     */
    if(rc < 0)
        return rc;

    return idx_offset;
}

/**
 * find unused alias number
 */
static int
_next_alias(char *if_name)
{
    int             i, j, k, sd, interfaces = 0, len;
    struct ifconf   ifc;
    struct ifreq   *ifrp;
    char                    *alias;
    int                     *alias_list;

    if (NULL == if_name)
        return -1;
    len = strlen(if_name);

    if ((sd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        snmp_log(LOG_ERR, "could not create socket\n");
        return -1;
    }

    interfaces = _get_interface_count(sd, &ifc);
    if(interfaces < 0) {
        close(sd);
        return -2;
    }
    netsnmp_assert(NULL != ifc.ifc_buf);
    DEBUGMSGTL(("access:ipaddress:container", "processing %d interfaces\n", interfaces));

    alias_list = malloc(interfaces * sizeof(int));
    if (NULL == alias_list) {
        close(sd);
        return -2;
    }

    ifrp = ifc.ifc_req;
    for(i=0,j=0; i < interfaces; ++i, ++ifrp) {

        if (strncmp(ifrp->ifr_name, if_name, len) != 0)
            continue;

        DEBUGMSGTL(("access:ipaddress:container",
                    " interface %d, %s\n", i, ifrp->ifr_name));

        alias = strchr(ifrp->ifr_name, ':');
        if (NULL == alias)
            continue;

        ++alias; /* skip ':' */
        alias_list[j++] = atoi(alias);
    }

    /*
     * clean up
     */
    free(ifc.ifc_buf);
    close(sd);

    /*
     * return first unused alias
     */
    for(i=1; i<=interfaces; ++i) {
        for(k=0;k<j;++k)
            if (alias_list[k] == i)
                break;
        if (k == j)
            return i;
    }

    return interfaces + 1;
}


/**
 *
 * @retval  0 : no error
 * @retval -1 : bad parameter
 * @retval -2 : couldn't create socket
 * @retval -3 : ioctl failed
 */
int
_netsnmp_ioctl_ipaddress_set_v4(netsnmp_ipaddress_entry * entry)
{
    struct ifreq                   ifrq;
    struct sockaddr_in            *sin;
    int                            rc, fd = -1;
    _ioctl_extras                 *extras;

    if (NULL == entry)
        return -1;

    netsnmp_assert(4 == entry->ia_address_len);

    extras = netsnmp_ioctl_ipaddress_extras_get(entry);
    if (NULL == extras)
        return -1;

    fd = socket(AF_INET, SOCK_DGRAM, 0);
    if(fd < 0) {
        snmp_log(LOG_ERR,"couldn't create socket\n");
        return -2;
    }
    memset(&ifrq, 0, sizeof(ifrq));

    if ('\0' == extras->name[0]) {
        char *name = netsnmp_access_interface_name_find(entry->if_index);
        int   alias_idx;

        if (NULL == name) {
            DEBUGMSGT(("access:ipaddress:set", "cant find name for index %d\n",
                       entry->if_index));
            close(fd);
            return -1;
        }

        /*
         * search for unused alias
         */
        alias_idx = _next_alias(name);
        snprintf(ifrq.ifr_name,sizeof(ifrq.ifr_name), "%s:%d",
                 name, alias_idx);
    }
    else
        strncpy(ifrq.ifr_name, extras->name, sizeof(ifrq.ifr_name));

    ifrq.ifr_name[ sizeof(ifrq.ifr_name)-1 ] = 0;

    sin = (struct sockaddr_in*)&ifrq.ifr_addr;
    sin->sin_family = AF_INET;
    memcpy(&sin->sin_addr.s_addr, entry->ia_address,
           entry->ia_address_len);

    rc = ioctl(fd, SIOCSIFADDR, &ifrq);
    close(fd);
    if(rc < 0) {
        snmp_log(LOG_ERR,"error setting address\n");
        return -3;
    }

    return 0;
}

/**
 *
 * @retval  0 : no error
 * @retval -1 : bad parameter
 * @retval -2 : couldn't create socket
 * @retval -3 : ioctl failed
 */
int
_netsnmp_ioctl_ipaddress_delete_v4(netsnmp_ipaddress_entry * entry)
{
    struct ifreq                   ifrq;
    int                            rc, fd = -1;
    _ioctl_extras                 *extras;

    if (NULL == entry)
        return -1;

    netsnmp_assert(4 == entry->ia_address_len);

    extras = netsnmp_ioctl_ipaddress_extras_get(entry);
    if (NULL == extras)
        return -1;

    fd = socket(AF_INET, SOCK_DGRAM, 0);
    if(fd < 0) {
        snmp_log(LOG_ERR,"couldn't create socket\n");
        return -2;
    }

    memset(&ifrq, 0, sizeof(ifrq));

    strncpy(ifrq.ifr_name, extras->name, sizeof(ifrq.ifr_name));
    ifrq.ifr_name[ sizeof(ifrq.ifr_name)-1 ] = 0;

    ifrq.ifr_flags = 0;

    rc = ioctl(fd, SIOCSIFFLAGS, &ifrq);
    close(fd);
    if(rc < 0) {
        snmp_log(LOG_ERR,"error deleting address\n");
        return -3;
    }

    return 0;
}

/**
 *
 * @retval -1 : malloc error
 */
static int
_get_interface_count(int sd, struct ifconf * ifc)
{
    int lastlen = 0, i;

    netsnmp_assert(NULL != ifc);

    /*
     * Cope with lots of interfaces and brokenness of ioctl SIOCGIFCONF
     * on some platforms; see W. R. Stevens, ``Unix Network Programming
     * Volume I'', p.435.  
     */

    for (i = 8;; i *= 2) {
        ifc->ifc_buf = calloc(i, sizeof(struct ifreq));
        if (NULL == ifc->ifc_buf) {
            snmp_log(LOG_ERR, "could not allocate memory for %d interfaces\n",
                     i);
            return -1;
        }
        ifc->ifc_len = i * sizeof(struct ifreq);

        if (ioctl(sd, SIOCGIFCONF, (char *) ifc) < 0) {
            if (errno != EINVAL || lastlen != 0) {
                /*
                 * Something has gone genuinely wrong.  
                 */
                snmp_log(LOG_ERR, "bad rc from ioctl, errno %d", errno);
                SNMP_FREE(ifc->ifc_buf);
                break;
            }
            /*
             * Otherwise, it could just be that the buffer is too small.  
             */
        } else {
            if (ifc->ifc_len == lastlen) {
                /*
                 * The length is the same as the last time; we're done.  
                 */
                break;
            }
            lastlen = ifc->ifc_len;
        }
        free(ifc->ifc_buf); /* no SNMP_FREE, getting ready to reassign */
    }

    return ifc->ifc_len / sizeof(struct ifreq);
}

/**
 */
static void
_print_flags(short flags)
{
/** Standard interface flags. */
    struct {
       short flag;
       const char *name;
    } map[] = {
        { IFF_UP,          "interface is up"},
        { IFF_BROADCAST,   "broadcast address valid"},
        { IFF_DEBUG,       "turn on debugging"},
        { IFF_LOOPBACK,    "is a loopback net"},
        { IFF_POINTOPOINT, "interface is has p-p link"},
        { IFF_NOTRAILERS,  "avoid use of trailers"},
        { IFF_RUNNING,     "resources allocated"},
        { IFF_NOARP,       "no ARP protocol"},
        { IFF_PROMISC,     "receive all packets"},
        { IFF_ALLMULTI,    "receive all multicast packets"},
        { IFF_MASTER,      "master of a load balancer"},
        { IFF_SLAVE,       "slave of a load balancer"},
        { IFF_MULTICAST,   "Supports multicast"},
        { IFF_PORTSEL,     "can set media type"},
        { IFF_AUTOMEDIA,   "auto media select active"},
    };
    short unknown = flags;
    int i;

    for(i = 0; i < sizeof(map)/sizeof(map[0]); ++i)
        if(flags & map[i].flag) {
            DEBUGMSGT_NC(("access:ipaddress:container","  %s\n", map[i].name));
            unknown &= ~map[i].flag;
        }

    if(unknown)
        DEBUGMSGT_NC(("access:ipaddress:container","  unknown 0x%x\n", unknown));
}